Submission #900482

#	Time	Username	Problem	Language	Result	Execution time	Memory
900482		Trisanu_Das	Spring cleaning (CEOI20_cleaning)	C++17	34 / 100	1064 ms	15356 KiB

cleaning

#include <bits/stdc++.h>
 
using namespace std;
typedef long long ll;
vector<int> adj[100002];
int leaf[100002];
int dp[100002];
ll ans = 0;
void dfs(int x, int p){
    dp[x] = leaf[x];
    for(auto u : adj[x]){
        if(u != p){
            dfs(u, x);
            dp[x] += dp[u];
        }
    }
    if(x == 1){
        if(adj[x].size() == 1 && leaf[x] == 0){
            if(dp[x] == 1){
                ans++;
                return;
            }
            else { ans = -1LL; return; }
        }
        if(dp[x]%2) { ans = -1LL; return; }
        else{
            ans += dp[x];
            return;
        }
    }
    if(dp[x] == 0){
        dp[x] = 1;
        return;
    }
    if(dp[x]%2){
        ans += dp[x];
        dp[x] = 1;
        return;
    }
    ans += dp[x];
    dp[x] = 2;
}
 
int main()
{
    int n, q;
    scanf("%d %d", &n, &q);
    for(int i=1;i<n;i++){
        int s, e;
        scanf("%d %d", &s, &e);
        adj[s].push_back(e);
        adj[e].push_back(s);
    }
    for(int i=1;i<=q;i++){
        fill(leaf, leaf + 30002, 0);
        int d;
        scanf("%d", &d);
        for(int i=1;i<=d;i++){
            int l;
            scanf("%d", &l);
            leaf[l]++;
        }
        ans = 0;
        dfs(1, -1);
        printf("%lld\n", ans);
    }
}

Compilation message (stderr)

cleaning.cpp: In function 'int main()':
cleaning.cpp:47:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   47 |     scanf("%d %d", &n, &q);
      |     ~~~~~^~~~~~~~~~~~~~~~~
cleaning.cpp:50:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   50 |         scanf("%d %d", &s, &e);
      |         ~~~~~^~~~~~~~~~~~~~~~~
cleaning.cpp:57:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   57 |         scanf("%d", &d);
      |         ~~~~~^~~~~~~~~~
cleaning.cpp:60:18: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   60 |             scanf("%d", &l);
      |             ~~~~~^~~~~~~~~~

• Subtask 1: 0 / 0
• Subtask 2: 9 / 9
• Subtask 3: 9 / 9
• Subtask 4: 16 / 16
• Subtask 5: 0 / 19
• Subtask 6: 0 / 17
• Subtask 7: 0 / 30